For a long time I was having trouble doing this level and I couldn't figure out why. I had done it once using the poisoned fish and it worked great but after I improved my speed it suddenly stopped working. I had changed my route so that I ran toward the car gate, across the driveway and back to the backyard gate and over to the end of the porch. I would crouch there and then after the two gate guards turned toward the car gate I would head to the other end of the porch.
I studied Hyamoto Jr's movements and found that when I went past the window to his room, he would go into an alerted state and stand in the corner of the room. I'm guessing once he gets nervous and stands in the corner, then he's not going to eat fish no matter how many plates the girl brings him. Keep this in mind when you see the pics of this level. All I had to do was walk past his window to make him nervous. So the goal of this level was to kill every other person in the yard and in the house including in his room without him leaving the table.
If you know this level, you know that there are two guards and some kind of body guard in this room with Hyamoto Jr. I was able to get the body-guard to come out into the hallway and took him out with a silenced round before he could fire a shot. This left the other two. After clearing the back yard completely, amazingly, one can sneak in through the doors to the deck and get the guard between the two halves of the room. The weirdest thing, though was that when I backed up into the far half of the room and took out the guy by the door with a headshot from the far corner, even though he fell to the ground just in six meters in front and to the right of Hyamoto Jr., Hyamoto still didn't seem to notice it!


